Attorney General Eric Holder attacked "stand-your-ground laws" three days after the acquittal of a man in last year's shooting of an unarmed Florida teen, saying in a speech that such laws encourage more violence than they prevent.

Speaking to the NAACP's annual convention in Orlando, Fla., not far from where George Zimmerman was tried for the shooting death of Trayvon Martin, Mr. Holder denounced laws that permit a person...